Generally, electrophotographic printers are classified, according to a developing manner, into a dry type electrophotographic printer, which employs powdered toner as a developer, and a wet type electrophotographic printer, which employs a mixture of toner and a liquid carrier such as noppar. In both types of electrophotographic printer, toner is supplied to a photosensitive medium, such as a photosensitive drum having an electrostatic latent image formed thereon, to form a certain image, and a sheet of paper is passed through a transfer medium rotated in contact with the photosensitive drum so that the developed image is printed on the sheet of paper.
Since the dry type electrophotographic printer employs powdered toner, it generates harmful toner dust due to the powdered toner.
However, since most printers and copiers currently available on the market are not provided with a suitable device for recovering toner dust, the fine toner dust is discharged to the outside through an exhaust hole.
In addition, since an office machine such as a computer is formed with an intake hole through which air is introduced into the office machine to cool the office machine, foreign matter such as dust is also introduced into and deposited inside the office machine therethrough, causing malfunction or failure of the office machine.